Device for drilling and enlarging holes



H. A. HABICHT. DEVICE FOR DRILLING AND ENLARGING HOLES.

APPLICATION FILED JULY 26.1920.

Patented Oct. 31, 1922.

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Patented Uct. 3i, T922.

ETENRY A. HAEICHT, OF INDIANAPOLIS, INDIANA.

DEVICE FOR DRILLING AND ENLARGING HOLES.

Application filed July 26,

1/ 0 alt to 7mm it may concern Be it known that I, HENRY A. I'IABIGHT, a citizen of the United States, residing at 111-. dianapolis, in the county of Marion and State of Indiana, have invented certain new and useful Improvements in Devices for Drilling and Enlarging Holes, of which the following is a specification.

This invention relates to a device for drilling and enlarging holes in metal boxes, being particularly adapted for use in the drilling of new holes or the reaming and enlargin of existing holes in metalboxes employed for enclosing the terminal ends of metal conduits which encase electric wires for lighting purposes, in both public and private buildings. I i

In conforming to certain special and specific municipal ordinances for the preven tion of fire, it is customary to install a metal box as a part of the electrical equipment for enclosing the ends of the metal conduits en closing the conductor wires. These boxes are provided with doors to render the interior accessible; are rather shallow compared with. their widths, and are usually located in out of the way places-on basement walls,

storage rooms, etc.,-where repairs aremade with difficulty and requiring considerable labor and time. Moreover, it frequently happens in public buildings and similar places, that the original plans and specifications for the lighting systems prove inade quate or insufiicient, or, asgenerally occurs,

additional lamps are added to the circuits from time to time until the capacity of the conductor wires is inadequate to carry the load, so that larger or a greater number of wires must be added, and incidentally neces'sitates larger conduits for enclosing the wires. The above mentioned changes require either an increase in. the number of openings in the terminal box or the enlarging of existing openings in the boy; in either case, this work is generally per. rined with an ordinary 'carpenters brace and a reamer, and in. view of the shallow charad ter of the box and the proirimity of thesurface of the wall the movement of the reamer is restricted from. a full rotation. to a limited oscillatory movement, so that this class of work in the art is characterized as being tedious, difficult, and one requiring much time.

One of the objects of the present invention is toobviate the above enumerated diificul- 1920. Serial No. 399,048.

. ties by the provision of a devicewhereby a new hole may be easily drilled or an existing hole readily enlarged, with precision, speed and economy.

A further object of the invention consists in the provision of a device of the above character whereby holes of different diameters may be drilled without interchanging the parts.

I accomplish the above objects of the invention, and such others as may appear from a perusal of the following description and claims, by means of the construction illustrated .in the accompanying drawings, forminga part hereof, in which- Figure 1. is a top or planview of my improved hole drilling and enlarging device. Fig. 2 is a view partly in vertical section and partly in side elevation of the device. Fig. 3 is a fragmentary detail View in front elevation of thechuck-head. Fig. 4 is a plan view of the face ofthe chuck-head. Fig. 4. i is a fragmentary detail plan view of one of the sliding boxes for supporting the tool holders, showing the means for 'adjusting same. Fig. 5 is a horizontal view, partly in section and partly in elevation, on the line 55 in Fig. 2. Fig. 6 is a perspective view of one of the tool holders for the mounting of the cutting tOOlSw, Fig. 7 is a perspective view of one of the adjustablesliding boxes for the mountingof the tool holders. .Fig. 8 is a fragmentary detail view in side elevation of the chuck-head, showing the device set or arranged for enlarging an existing hole.

Referring to the drawings, the body of the device comprises a metal frame 10, which is formed U-shaped and terminating. in the arms A and B which support the rotating parts of the device. The peculiar shape of frame 10 is such that its free ends may readily be inserted into the ordinary form of a metal box 11 forming the enclosure for the terminal ends of the conduits for en; closing electric wires.

Passing transversely through arm A. a revoluble shaft 15. havinga squared. end 16. so that said shaft may be rotated by means of an ordinary wrench. The lower portion of shaft 15 has its diameter slightly reduced to form a shoulder 17 and said shaft immediately below shoulder 17 is provided with threads to receive a threaded ring 18 which is adjusted on shaft 15 to abut and lock against shoulder; 17, whereby shaft 15 is arranged in a key-way 22 in shaft 15.

The upper end of head is reduced in diameter and is provided with threads which are adapted to engageeorresponding threads in the internal wall of a collar 23. Collar 23 may freely rotate with head 20 but the collar is held against longitudinal movementthrough its engagement with a channel 24.- which is formedbv reducing the d1 aineter of the lower end of threaded ring 18 and a shoulder formed by a disk-ring 25 which is secured to the lower face of ring 18 by means of the screws 26. The above construction contemplates that when shaft 15 is rotated a corresponding movement is imparted tochuclr-head 20. Head 20 provides the means for slidably mounting the cutter blades for the drilling of new holes or the enlarging of existing holes, in the heretoforementmned metal boxes. To ac: complish the above purposes, head 20, as shown in Fig. 1, is provided in its face with a T-shaped slot 3Ov which is adapted to re ceive a pair of radially adjustable boxes 31 (Fig. 7 which provide the means for mounting and adjusting of the tool holders .32 radially of the axis of head 20. As

stated, sliding boxes 31 are susceptible of radial adjustment in head 20 so that the distance of the cutter blades may beincreasedand decreased fromthe axis of the head. 20 to enable holes of different diameters'to be drilled, and sliding boxes 31 may be secured at any point along slot 30 by means of the set-screws 341. Each sliding box-31 is provided with a T-shaped channel '35 which is adapted to receive and guide one of the tool holders 32. With the above construction, the cutter blades are arranged on opposite sides and at uniform distances from the center of chuck-head 20, which adjustment is secured bymeans of the sliding boxes 31, and any minute adjustments neces sary to bring the cutter blades an exact uniform distance from the axis of head'QO is effect-ed by the independent adjustment of the tool holders 32 by means of the adjust-- ing screws 38. Screws 38 are threaded throughout their entire length and. pass through threaded apertures in tool holders 32, and, as indicated in Fig. 4 the inner ends'of screws .38 are each'provided with I an annular groove-39. The inner ends of screws 38 are inserted into suitable apertures'in'the rear walls of channels 35, and;

tion in which said screws are rotated. 41

represents the cutter blades which are formed out of especially hardened steel, and. these blades are detachably secured in suitable notches in the rear faces of the tool holders 32 by means of the screws 4.4. By means ot this construction'the cutter blades 4:1 may easily be replaced when worn or broken, without the necessity of discarding any oi the remaining parts of the device.

Examining Fig. 2, it will be observed that the device is usually arranged so that the arm A, containing the drilling mechanism, will be introduced into the interior of metal box 11. When properly adjusted for the drilling of a hole, the centering head50, which is reinovably arranged in the lower end of shaft '15, rests upon the surface of either the horizontal or vertical walls of box 11. Arm B of the device carries a clamping-bolt 51 which is provided with peripheral threads which engage suitable threads in a threaded aperture in said arm. The lower end of clamping-bolt 51 is squared. as at 52, so that the removable head. 53 may be set firmly against the ex ternal surface of box 11, whereby the metal to be removed in forming the proposed opening is firmly held during the cutting operation. 1

The device is also provided withautomatic feed mechanism so that the cutter blades 11 are moved or at vanced intermittently and accorded a predeterminedamount of travel, which. is suliicieut to correspond with the cutting capacity of thecutter blades 41, in cutting and removing the material. As shown in 5, the automatic feed mechanism comprises a. crescent shaped spring 60 which is pivoted at its center to the under side of arm A. by means of a screw 61, and

the free ends of the spring 60 are bent in reverse curves to iform the projections 62 which project into the path traveled by a pair of pins 63 which are mounted upon the upper end of the collar 23. When shaft 15 is rotated collar 23 and chuck-head 20 rotate in unison until pins 63 contact pro; jections 62 on spring 60 when further rotation of collar 23 is momentarily arresteduntil the applied stress expands or forces apart the slowly expanding free ends of spring 60 a sufficient distance to permit the passage of pins 63, after which collar 23 is again free to rotate with head 20 until its movement is again arrested by the re-enmentioned momoi'itary pause oi the internally threaded collar 23, the cut'orced continued rotation oi head 20, by means oi the feather 21., causes the latter to move downwardly by reason of its threaded con nection with collar 23 whereby cutter blades 4-1 are forced intermittently into the metal during the operation of cutting.

Figure 8 illustrates the device when adjusted for the enlarging of an existing hole in metal box 11. In this operation, usually on account of the diameter of the existing hole I provide the spindle end of shaft .15 with a clamping head 51 of suilicient diameter to more than. extend across the existing hole, so that a limo footing for said head secured on the metal lying contiguously about the can isting hole, as clearly shown in Fig 8, It is also desirable in enlarging holes to provide a firm {noting tor the metal box on its under side, and. with this end in view I preterably employ a wooden block 70 which is interposed between the head 01? clamping" bolt 51 and. the adjacent surface of box 11; so that an extended. area of the surface of the box firmly held during the cutting operation. and preventing thereby possible injury to the cutter blades ll.

Having thus -fully described my said invention, what I desire to secure by Letters Patent, is

1. In combination in a machine for cutting holes, of a frame having a pair of parallel spaced arms a revoluble shaft projecting transversely tlu'oi'lgi'h one of said arms and having its lower exposed portion reduced in diameter to provide a shoulder, a ring threaded on the reduced portion of the shaft and abutting the shoulder, an. internally threaded collar engaging at one end an annular groove in the ring, a removable tool holding head keyed on the shaft and having external threads to engage the internal threads of the collar, and a clamp-screw carried by the second arm of the frame for impinging the material worked upon against the centering head of the revoluble shaft.

2. A. device of the character described, a rotary shaft, ahead having independent longitudinal travel of the shaft but enforced rotary movement with the latter, peripheral threads on one external end of the head, an internally threaded collar arranged. on the rotary shaft, a pair of diametrically positioned pins arranged on the external surface of the collanand means comprising a U- shaped spring having an intermediate attachment to the fame with the free ends of the spring arranged to alteri'iately engage the pins and temporarily arresting the movement of the collar during each I'GVOlIL tion of the rotary shaft.

In witness whereof, I have hereunto set my hand and seal at Indianapolis Indiana. this 24th day of July, A. 13., one thousand nine hundred and twenty.

HENRY A. HABICHT. [Ls] 

